The present invention relates to a microscope support foot for receiving optical and electronic components of an illumination arrangement as well as a drive unit for the optical components. The support foot has a central portion, respective lateral portions integral therewith, carrying a hand rest, and a base plate covering the microscope support foot.
German Offenlegungsschrift No. 2,451,884 discloses a microscope support, in the foot of which a dish-shaped carrier is securable to receive electrical components which serve for controlling the illumination. In the interior of the foot, an optical system is additionally arranged, which directs a beam of light through a projection lens to a converging lens. Only the carrier is to be handled for the assembly and the maintenance of the electrical components. No information on the arrangement of the optical system and the functions thereof can be inferred from this publication.
In another known microscope support, optical and electrical components of the illumination arrangement are disposed in the foot. the foot has a central portion and two lateral portions, and is covered by a base plate. The lateral portions carry hand rests and permit an ergonomic posture of the arm during use of the microscope. Optical components are mounted in the central portion of the foot as part of an illumination arrangement, namely an illumination lens, a deflecting mirror and a variable light field stop. The aperture of the latter is adjustable by means of a knurled wheel secured in the support foot. In this microscope, a similarly variable aperture stop is a component of the converging lens and is operated by means of an adjusting wheel or lever disposed on this lens arrangement.
Not least because of the construction of its foot which is provided with stiffening ribs in the interior, such a microscope support exhibits a high mechanical stability, but is not free from disadvantages. In view of the increased requirements regarding the power of the illumination arrangement, it is indeed possible to replace the conventional electrical components, such as transformers, by electronic switching components (transistors etc.) with lower heat losses. However, especially in long-term operation of a microscope, the heat loss invariably leads to interfering alterations in focus. A support foot construction promoting the circulation of air gives rise to increased formation of dust and requires frequent cleaning of the optical components of the illumination arrangement, which likewise interferes with long-term operation. Moreover, as a result of the position of the light field stop in the microscope support foot and the position of the aperture stop in the converging lens, joint operation of these stops by means of the drive means associated with them is not possible.